Portable sawmill

Abstract

A sawmill includes a four-stroke internal combustion engine having an output shaft for driving a sawblade. The output shaft has a longitudinal axis. The engine is mounted on the sawmill for rotation between a first operative position with the longitudinal axis of the output shaft extending at a first angle, and a second operative position with the longitudinal axis of the output shaft extending at a second angle transversely to the first angle. The engine has fuel injection to facilitate operation in the first and second operative positions and a lubrication system incorporating a wet sump. An oil pick up for the lubrication system is configured to pick up oil from the wet sump at both the first and second operative positions.

The invention claimed is: 
     
       1. A sawmill comprising:
 a four-stroke internal combustion engine including: 
 an output shaft for driving a sawblade, the output shaft having a longitudinal axis; and a crankcase having an opening for assembly of at least a crankshaft and piston, and 
 a closure covering the opening; 
 a support framework, the engine being selectively pivotable relative to a portion of the support framework between a first operative position with the longitudinal axis of the output shaft extending at a sideways angle, and a second operative position with the longitudinal axis of the output shaft extending at a downwards angle transversely to the sideways angle, the engine having fuel injection configured to facilitate operation in both the first and second operative positions; and 
 a lubrication system configured to circulate an amount of lubricant corresponding to a predetermined capacity for the engine, wherein the crankcase incorporates a wet sump, wherein the wet sump is defined by a first wet sump region open to the crankcase for collection of lubricant in the first operative position of the engine, the lubricant collecting up to a first liquid level in the first wet sump region when said amount of lubricant is supplied to the engine, with the depth of the crankcase being such that the crankshaft is clear of the first lubricant level, 
 the wet sump being further defined by a second wet sump region in the closure for collection of lubricant in the second operative position of the engine, the lubricant collecting up to a second liquid level in the second wet sump region when said amount of lubricant is supplied to the engine, the depth of the closure being greater than the depth of the second lubricant level, 
 wherein the lubrication system includes an oil inlet disposed at an intersection of the first wet sump region and the second wet sump region. 
 
     
     
       2. The sawmill as claimed in  claim 1 , wherein the depth of the first and second wet sump regions when the engine is in respective first and second operative positions is such that clearance is provided between at least the crankshaft and the connecting rod or rods and the first and second lubricant levels respectively. 
     
     
       3. The sawmill as claimed in  claim 2 , wherein the depth of the first and second wet sump regions when the engine is in respective first and second operative positions is such that clearance is provided between at least the crankshaft, the connecting rod or rods and timing gears, and the first and second lubricant levels respectively. 
     
     
       4. The sawmill as claimed in  claim 1 , wherein the output shaft exits through the closure. 
     
     
       5. The sawmill as claimed in  claim 4 , wherein the output shaft is in-line coupled to a sawblade shaft for mounting of the sawblade. 
     
     
       6. The sawmill as claimed in  claim 1 , wherein there is a single oil inlet for the lubrication system. 
     
     
       7. The sawmill as claimed in  claim 6 , wherein the single oil inlet is in fluid communication with a single pump of the lubrication system. 
     
     
       8. The sawmill as claimed in  claim 1 , wherein the first and second operative positions extend substantially orthogonal to each other. 
     
     
       9. The sawmill as claimed in  claim 8 , wherein the first and second operative positions are the only selectable operative positions. 
     
     
       10. The sawmill as claimed in  claim 9 , wherein, in the first operative position, the longitudinal axis of the output shaft is arranged substantially horizontally and in the second operative position, the longitudinal axis of the output shaft is arranged substantially vertically to extend below the engine. 
     
     
       11. The sawmill as claimed in  claim 1 , further including a pivot body pivotably mounted to said portion of the support framework, the engine being secured to the pivot body. 
     
     
       12. The sawmill as claimed in  claim 11 , wherein the pivot body includes pivot portions to provide the pivotable mounting and a mounting portion for mounting of the engine. 
     
     
       13. The sawmill as claimed in  claim 12 , wherein the pivot portions define a pivot axis which extends transversely to the longitudinal axis of the output shaft and is substantially coincident with the longitudinal axis. 
     
     
       14. The sawmill as claimed in  claim 12 , wherein the pivot body further includes a housing portion such that the output shaft exited from the engine or motor is enclosed between the pivot body and the engine/motor. 
     
     
       15. The sawmill as claimed in  claim 14 , wherein the output shaft is coupled to a saw shaft via a clutch or a cush-drive and the housing portion surrounds the clutch or the cush-drive. 
     
     
       16. The sawmill as claimed in  claim 15 , wherein the saw shaft is supported by a bearing that is surrounded by the housing portion. 
     
     
       17. The sawmill as claimed in  claim 14 , wherein the pivot portions, the mounting portion, and the housing portion are formed as a unitary part. 
     
     
       18. The sawmill as claimed in  claim 14 , wherein the pivot body including the pivot portions, the mounting portion and the housing portion is a unitarily cast part. 
     
     
       19. The sawmill as claimed  claim 1 , wherein the first and second wet sump regions are defined by surfaces of the crankcase and closure, respectively, which are shaped as open trays. 
     
     
       20. The sawmill as claimed in  claim 1 , wherein the sawmill is a portable sawmill configured to be transported to a remote location with the support framework being assembled over the top of a felled log in situ.